1. Field of the Invention
The present invention relates to an image display for displaying an image (in particular, characters, figures, symbols, or the like) on a scanning-type display of a personal computer, a video game machine or the like.
2. Description of the Related Art
Japanese Patent Publication No.2-7478 discloses a TV game machine. In the machine, in order to display a plurality of moving-picture characters, a number of shift registers are provided, the number of shift registers being the same as the number of moving-picture characters which can be displayed in one scanning period. Data is shifted according to respective moving-picture character display timing. Japanese Patent Publication No.2-44078 discloses a scanning-type display control method. In the method, two sets of buffers, each set including a row buffer and a column buffer, are provided. A CPU writes attribute information of a moving sample into attribute-information storing means, the moving sample being displayed on a CRT display. Other than the writing duration, the CPU can perform other processing such as game control processing.
In the above-mentioned prior art, generally, a character having a fixed size can be handled. In order to achieve display of a character having a larger size, the larger character consists of a plurality of fixed-size divisions. However, in such a method, in order to move the larger character, it is necessary to perform attribute information alteration for each fixed-size division. Thereby, the software scale should be increased and the CPU working efficiency may be degraded.
In order to solve such a problem, Japanese Patent Publication No.4-43595 discloses a moving-picture display device. In the device, when video data is written in an editing memory which stores information to be displayed in one scanning line as scanning-line video data, the writing is controlled with horizontal display size information. Thereby, a plurality of moving-picture figures having different display sizes are displayed in a mixed manner.
However, in this device, video data writing is controlled based on horizontal display size information as mentioned above. Thereby, it may not be possible to efficiently access a memory which has previously stored video data.